The present invention generally relates to electrical power distribution apparatus, and more particularly relates to low cost, multi-function, rack mountable electrical power distribution apparatus and systems.
Research and development of computer technology has continually produced smaller and more compact systems. However, electrical power distribution units and systems for supplying power to electrical devices, such as computers and other critical equipment, in a building or other facility have remained bulky and sometimes difficult to work with.
Conventionally, electrical power coming into a facility passes into a free-standing power distribution unit (PDU) that includes a substantial plurality of output circuits. Each of these circuits is hard-wired to cables which are passed through conduits for distances of up to about 200 feet or more, to individual components of critical equipment. A total conduit run of up to about 3000 feet per PDU can occur. This wiring is often run through floors and walls of the facility during the electrical wiring phase of building construction. Electrical outputs initiating from such free-standing PDUs are typically provided as cables that are accessible through walls and floors of the facility.
Electrical needs in a building frequently change, typically by an increase in demand for more output circuits to accommodate more pieces of equipment. Power strips including a number of plug receptacles and having a single circuit breaker may be connected to a wall receptacle. However, in many cases, a power strip is not appropriate or sufficient for large scale changes in electrical needs, or for accommodating additional pieces of critical equipment which requires hard-wired connections to the power source.
The process of re-cabling electrical output circuits from the PDU, for example, to more strategic locations within the facility, is a costly, labor intensive task, which typically requires the work of outside contractors who specialize in electrical cabling and rewiring. Because of the inherent difficulty of accessing a specific wire or cable from the numerous, and sometimes tangled masses of cables and wires concealed within walls or floors of the facility, obsolete and unusable cables are often left in place adding to the confusion and difficulty of maintaining or controlling such wiring.
Clearly, there is a need for power distribution units and systems that address the concerns presented by conventional systems.
New electrical power distribution apparatus and systems have been discovered. The present apparatus are compact in design, cost effective and labor and time saving. The present apparatus and systems provide versatility and flexibility in meeting electrical power requirements in both large and small facilities.
In one broad aspect, electrical power distribution apparatus in accordance with the invention comprise a housing and an electrical power input assembly, preferably located substantially in the housing, adapted to be connected to an electrical power supply, for example, a commercial power supply, preferably an uninterruptible power supply or UPS, which is provided from a conventional power source, e.g., generating plant. The apparatus, and in particular, the housing, preferably is rack-mountable, for example, on a conventional 19 inch or 23 inch industry standard rack. This rack mountable feature is highly advantageous in that the present apparatus is compact, can be placed on a rack for easy installation and maintenance. This rack mountable feature provides the present apparatus with substantial benefits relative to conventional, free standing and large or bulky PDU""s.
The apparatus in accordance with the invention further comprises a plurality of electrical power output assemblies, preferably located substantially in the housing, adapted to receive electrical power from the power input assembly. The power output assemblies may be mounted in a circuit panel that is removably mounted in the housing. Preferably, the plurality of output assemblies includes at least one output connection adapted to be hard-wired, for example, to a piece of equipment in a manner similar to hard-wiring equipment to a conventional power distribution unit. The plurality of output assemblies may, and preferably does, also include at least one output receptacle adapted to receive an equipment plug to provide electrical power, for example, to the equipment associated with the equipment plug. Thus, the present apparatus are effective in coupling directly to local pieces of equipment through conventional receptacles, as well as being hard-wired to remote pieces of equipment, or alternatively to one or more additional separate power distribution apparatus in accordance with the present invention. It is noted that the hard-wired output connection may hereinafter sometimes be referred to as an xe2x80x9cexternal circuitxe2x80x9d, and the output receptacle or receptacle circuit may hereinafter sometimes be referred to as an xe2x80x9cinternal circuitxe2x80x9d.
In one advantageous embodiment of the invention, the plurality of output assemblies may include a plurality of differently configured receptacles adapted to receive differently configured equipment plugs. This feature advantageously adds to the flexibility of the present apparatus.
In another aspect of the invention, each of the external circuits and/or internal circuits includes a different, individually operable circuit breaker, although more than one circuit, such as two or more internal circuits, can be associated with the same circuit breaker.
Unlike large, free-standing power distribution units, the present electrical power distribution apparatus may be adapted for receiving and distributing single phase power, thus making it convenient for small electrical applications. The apparatus, however, may also be adapted for use with a three phase power. Advantageously, the input assembly is adapted to be electrically connected to a single phase electrical power supply, or alternately to a three phase electrical power supply.
Preferably, the electrical power input assembly further comprises a meter, for example, located substantially in the housing, adapted to monitor at least one property of the electrical power passing through the input assembly. For example, the meter may be a voltage meter for monitoring voltage being provided to the apparatus. More sophisticated meters may be employed to provide enhanced electrical power monitoring. For example, a multi-function monitor, such as the 7300 ION-TRAN model sold by Power Measurement, may be advantageously employed.
In addition, a transformer, for example, a step down transformer, may be provided. The transformer preferably is adapted to be in electrical communication with both the electrical power supply and the input assembly. Because of the compact nature of the present apparatus, the transformer, which is often a substantial source of heat, preferably is located outside the housing, for example, in the outdoors or other environment where the heat produced can be effectively dissipated.
In an additional aspect of the present invention, electrical power distribution systems are provided. The present systems generally comprise a plurality of electrical power distribution apparatus configured such that each electrical power distribution apparatus is adapted to be electrically connected with at least one of the other electrical power distribution apparatus. At least one, and preferably more than one, of the electrical power distribution apparatus included in the present systems is an apparatus in accordance with the present invention, for example, as described herein.
In one very useful embodiment, the present systems provide a single primary electrical power distribution apparatus in electrical communication with one or more electrical power distribution apparatus in accordance with the present invention, for example, hardwired to the primary power distribution apparatus through an output connection of the primary electrical power distribution apparatus. Such systems very effectively distribute electrical power while reducing the amount of wiring required for such distribution. Since each of the power distribution apparatus included in the present systems preferably are effective to provide both receptacle circuits and hardwired circuits, each individual power distribution apparatus making up the system is able to provide power to pieces of equipment located close to the power distribution apparatus, for example, using the receptacle circuits, and to pieces of equipment which are relatively remote from the power distribution apparatus, for example, using the output connections which are adapted to be hardwired to such pieces of equipment. The use of the present power distribution apparatus in such electrical power distribution systems takes advantage of the flexibility and versatility of the present electrical power distribution apparatus.
Any and all features described herein and combinations of such features are included within the scope of the present invention provided that the features of any such combinations are not mutually inconsistent.
These and other aspects of the present invention will become apparent in the following detailed description, particularly in conjunction with the accompanying drawings in which like parts bear like reference numerals.